THEME WIRELESS
MULTIPHYSICS SIMULATIONS FOR 5G RFICS AND SOCS The transition to 5G is exciting but no small task given the degree of complexity at various points in the system. Multiphysics simulations simultaneously solve power, thermal, variability, timing, electromagnetics and reliability challenges across the spectrum of chip, package and system to promote first-time silicon and system success. Laurent Ntibarikure
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ystem-on-chips (SoCs) and radio frequency integrated circuits (RFICs) for 5G smartphones and networks need to manage huge amounts of antenna data and offer significantly high processing capabilities in thermally and power-constrained environments. The growing interdependence of various multiphysics effects like timing, power, electromagnetics, thermal and reliability in sub-16nm designs poses significant challenges for design closure. Traditional margin- driven, silo-based design approaches to the chip, package and board have limited simulation coverage and fail to unravel potential design weaknesses, causing field failures. Multiphysics simulations simultaneously solve power, thermal, variability, timing, electromagnetics and reliability challenges across the spectrum of chip, package and system. Early analysis is key, but this comes with some requirements for SoC and intellectual property (IP) designs. The most important ones pertain to power efficiency, power integrity, reliability, advanced packaging and electromagnetic crosstalk.
Power
The shift from 4G to 5G is expected to deliver a spike in cell edge data rates from 10 Mb/s to more than 1 Gb/s, plus a 50 percent gain in energy ef32
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ficiency. For evolving generations of 5G implementations, the main focus is on predicting power profiling early in the chip design phases. Specific attention has to be paid to spectrum- related issues, traffic characteristics, radio interference and interoperability and network access-related issues. Power efficiency is a key design consideration for 5G devices. Average power, peak power, peak change in power and sustained worst-case average power are all important for thermal robustness, power integrity and cost of system operation. Early feedback is critical to achieving 5G power targets. For 5G SoCs, power grid signoff through traditional approaches isn’t feasible. This is due to severe routing constraints that can potentially cause timing convergence issues down-
stream. For advanced FinFET technology processes, the power grid’s node count is very high and any reduction in node count will affect accuracy. With very small design margins, power signoff solutions leave little margin for error. The slightest inaccuracy can result in product failure. It’s important, therefore, to analyze the entire power grid flat rather than partitioning the design with a “divide and conquer” approach. The need to model electromagnetic effects from DC up to mm-wave calls for special handling of layouts.
Reliability
Design for reliability is another key consideration for advanced SoCs used in 5G communication systems. These SoCs, for example, will be instrumental in enabling future mission- critical applications like self-driving cars. Reliability issues can be challenging at advanced Fin-
